The invention relates to fluid-heating apparatus, such as a storage-type water heater, and methods of operating the apparatus, such as to reduce energy consumption by the storage-type water heater while providing sufficient hot water to users.
Storage-type water heaters are commonly used to provide hot water to residential users. As the cost of energy has continued to rise, attempts have been made to reduce the amount of energy used by these water heaters. Insulation has been employed to reduce the radiant loss of heat from the storage tank, and therefore, reduce the need to reheat the water and to use additional energy. Controllers have been provided which monitor usage patterns and heat water only during periods when demand for hot water is expected or energy costs are low. These methods, while reducing energy usage, can still use energy beyond what is necessary to provide adequate hot water to the user.